Comparison of patterns and rates of cement leakage in percutaneous sacroplasty for sacral insufficiency fractures versus neoplasia

OBJECTIVE

Percutaneous sacroplasty is a minimally invasive procedure which utilises injection of bone cement into the sacrum for stabilisation of osteoporotic sacral insufficiency fractures (SIF) and neoplastic lesions to relieve pain and improve function. While effective, cement leakage is an important complication associated with the procedure. This study aims to compare the incidence and patterns of the cement leakages following sacroplasty for SIF versus neoplasia and discuss the various patterns of cement leakage and their implications.

MATERIALS AND METHODS

This retrospective study analysed 57 patients who underwent percutaneous sacroplasty at a tertiary orthopaedic hospital. Patients were divided into 2 groups of SIF (n=46) and neoplastic lesions (n=11) based on their indication for sacroplasty. Pre- and post-procedural CT fluoroscopy was used to assess for cement leakage. The incidence and patterns of cement leakage were both compared among the two groups. A Fisher's exact test was used for statistical analysis.

RESULTS

Eleven (19%) patients had cement leakage on post-procedural imaging. The most common sites of cement leakage were into the presacral region (6), followed by sacroiliac joints (4), sacral foramina (3) and posterior sacral (1). There was a statistically significant higher incidence of leakage in the neoplastic group in comparison to SIF group (P-value <0.05). The incidence of cement leakage in the neoplastic group was 45% (n = 5/11) versus SIF 13% (n=6/46).

CONCLUSION

There was a statistically significant higher incidence of cement leak in sacroplasties conducted for the treatment of neoplastic lesions compared to those with sacral insufficiency fracture.

Acute pyelonephritis in pregnancy and plasma syndecan-1: evidence of glycocalyx involvement

BACKGROUND

Acute pyelonephritis, a risk factor for maternal sepsis, adult respiratory distress syndrome, and preterm labor, is a frequent cause of hospitalization. This condition is characterized by excessive intravascular inflammation and endothelial cell activation and dysfunction. Syndecan-1, a major component of the glycocalyx, is a gel-like layer that covers the luminal surface of healthy endothelial cells, preserving and mediating many endothelial functions. During pregnancy, there is an additional potential source of syndecan-1, the "syncytiotrophoblast glycocalyx," which lines the intervillous space. Insults that damage the glycocalyx lead to a shedding of syndecan-1 into the circulation. Hence, syndecan-1 has been proposed as a marker of endothelial injury in conditions such as sepsis, trauma, cardiovascular disease, and diabetes mellitus.

OBJECTIVE

The objective of this study was to determine whether the plasma syndecan-1 concentration changes in women with acute pyelonephritis in the presence or absence of bacteremia.

STUDY DESIGN

This cross-sectional study included three groups: (1) non-pregnant women (n = 25); (2) women with an uncomplicated pregnancy from whom samples were collected preterm (n = 61) or at term (n = 69); and (3) pregnant women diagnosed with acute pyelonephritis from whom samples were collected at the time of diagnosis during the second and third trimesters (n = 33). The diagnosis of acute pyelonephritis was based on clinical findings and a positive urine culture for bacteria. Blood culture results were available in 85% (28/33) of women with acute pyelonephritis. Plasma concentrations of syndecan-1 were determined by a validated immunoassay.

RESULTS

(1) Women with an uncomplicated pregnancy had a higher plasma concentration of syndecan-1 than non-pregnant women. The geometric mean (95% confidence interval [CI]) of syndecan-1 concentration was 51.0 (12.1-216.1) ng/mL in non-pregnant controls; 1280 (365-4487) ng/mL in normal preterm gestations; and 1786 (546-5834) ng/mL in normal term gestations (adjusted p < .005 for all three between group comparisons); (2) plasma syndecan-1 concentrations increased with gestational age among women with a normal pregnancy (p < .001, R² = 0.27); (3) syndecan-1 multiple of the mean (MoM) values in pregnant patients with acute pyelonephritis were higher than those in normal pregnant women based on second- and third-trimester samples (p = .048, 1.26-fold change). The increase was driven primarily by cases with a positive blood culture (p = .009, 1.74-fold change); (4) when data from third-trimester samples were compared, overall differences in syndecan-1 MoM values between cases and controls were slightly larger (p = .03, 1.36- fold change), which were especially contributed to by cases with a positive blood culture (p = .023, fold change 1.79-fold change).

CONCLUSIONS

Plasma syndecan-1 concentration is higher in pregnant women and increases as a function of gestational age. Patients with acute pyelonephritis have a higher plasma concentration of syndecan-1, and this is particularly the case in the presence of bacteremia.

Active video games and weight management in overweight children and adolescents-systematic review and meta-analysis

BACKGROUND

The prevalence of childhood obesity has been increasing for several decades. Active video games (AVG) may be an effective intervention to help manage this rising health crisis. The aim of this review is to evaluate whether AVG are effective at reducing weight or improving body composition in overweight youths.

METHOD

Medline, Embase, SportDiscus, ASSIA, CINAHL Plus, CENTRAL, CDSR and PsychINFO databases were searched for studies assessing quantitative or qualitative impact of AVG in overweight adolescents published in English. Three authors screened the results using inclusion/exclusion criteria.

RESULTS

A total of 12 studies met the inclusion criteria; 11 reported a significant decrease in at least one weight outcome. Results from seven randomized controlled trials were pooled by meta-analysis, which compared with controls subjects in AVG groups demonstrated greater body mass index (BMI) Z-score reduction (mean difference: -0.09 (-0.12, -0.05) I2 = 34%, P < 0.0001). The mean weight reduction (-2.66 Kg (-5.67, +0.35) I2 = 0%, P = 0.08) and BMI (-2.29 (-4.81, +0.22) I2 = 49%, P = 0.07) were greater in AVG groups but results did not reach statistical significance.

CONCLUSIONS

BMI Z-score was significantly reduced in the AVG group and the majority of included studies reported significant results in at least one weight outcome, suggesting AVG can be used to reduce weight or improve body composition in overweight youths. Further studies investigating the long-term sustainability of this change in body composition are needed.

Collagenase treatment reduces the anisotropy of ultrasonic backscatter in rat myocardium by reducing collagen crosslinks

Dysregulation of collagen deposition, degradation, and crosslinking in the heart occur in response to increased physiological stress. Collagen content has been associated with ultrasonic backscatter (brightness), and we have shown that the anisotropy of backscatter can be used to measure myofiber alignment, that is, variation in the brightness of a left ventricular short-axis ultrasound. This study investigated collagen's role in anisotropy of ultrasonic backscatter; female Sprague-Dawley rat hearts were treated with a collagenase-containing solution, for either 10 or 30 min, or control solution for 30 min. Serial ultrasound images were acquired at 2.5-min intervals throughout collagenase treatment. Ultrasonic backscatter was assessed from anterior and posterior walls, where collagen fibrils are predominately aligned perpendicular to the angle of insonification, and the lateral and septal walls, where collagen is predominately aligned parallel to the angle of insonification. Collagenase digestion reduced backscatter anisotropy within the myocardium. Collagen remains present in the myocardium throughout collagenase treatment, but crosslinking is altered within 10 min. These data suggest that crosslinking of collagen modulates the anisotropy of ultrasonic backscatter. An Anisotropy Index, derived from differences in backscatter from parallel and perpendicularly aligned fibers, may provide a noninvasive index to monitor the progression and state of myocardial fibrosis.

Pain Management Program in Cardiology: A Template for Application of Normalization Process Theory and Social Marketing to Implement a Change in Practice Quality Improvement

Quality improvement plays a major role in healthcare, and numerous approaches have been developed to implement changes. However, the reasons for success or failure of the methods applied often remains obscure. Normalization process theory, recently developed in sociology, provides a flexible framework upon which to construct quality improvement. We sought to determine if examination of a successful quality improvement project, using normalization process theory and social marketing, provided insight into implementation. We performed a retrospective analysis of the steps taken to implement a pain management program in an electrophysiology clinic. We mapped these steps, and the corresponding social marketing tools used, to elements of normalization process theory. The combination of mapping implementation steps and marketing approaches to the theory provided insight into the quality-improvement process. Specifically, examination of the steps in the context of normalization process theory highlighted barriers to implementation at individual, group, and organizational levels. Importantly, the mapping also highlighted how facilitators were able to overcome the barriers with marketing techniques. Furthermore, integration with social marketing revealed how promotion of tangibility of benefits aided communication and how process co-creation between stakeholders enhanced value. Our implementation of a pain-management program was successful in a challenging environment composed of several stakeholder groups with entrenched initial positions. Therefore, we propose that the behavior change elements of normalization process theory combined with social marketing provide a flexible framework to initiate quality improvement.

Association between respiratory rate oxygenation index and need for positive pressure ventilation in children on high flow nasal cannula for bronchiolitis

Our objective was to evaluate the association of respiratory rate oxygenation index (ROX) with the need for positive pressure ventilation in children < 2 years of age with bronchiolitis on high flow nasal cannula (HFNC) therapy. We performed a single-center prospective observational study of a convenience sample of children < 2 years of age with bronchiolitis who had HFNC initiated in the pediatric emergency department between November and March, 2018-2020. ROX was calculated as pulse oximetry/FiO₂/respiratory rate at HFNC initiation. Demographics, need for positive pressure ventilation (PPV), disposition, and hospital length of stay were collected. Logistic regression model was used to determine the odds ratio for PPV need relative to the highest ROX quartile. Of the 373 patients included, 49 (13.1%) required PPV. ROX was lower in patients who required PPV compared with those who did not (5.86 [4.71-7.42] vs. 6.74 [5.46-8.25]; p = 0.01). Logistic regression revealed that those patients whose ROX was in the lowest quartile (< 5.39) were three times more likely to require PPV compared to those in the highest quartile (> 8.21). These results held true after adjusting for confounders (odds ratio 3.1; 95% CI [1.3 to 7.5]; p = 0.02). The model's AUROC (0.701) indicated acceptable discrimination between cases and controls.

CONCLUSION

Low ROX index was associated with the need for PPV in children with bronchiolitis on HFNC. The risk stratification provided and ROX threshold for risk stratification require confirmation in other populations with a larger sample size.

WHAT IS KNOWN

• Demographic and clinical factors associated with high flow nasal cannula (HFNC) therapy in children with bronchiolitis has been studied.

WHAT IS NEW

• This is the first study to  report the utility of association of Respiratory Rate Oxygenation (ROX) index for need for positive pressure ventilation (PPV) in children  < 2 years of age with bronchiolitis on HFNC therapy. • ROX was lower in children who required PPV and children whose ROX was in the lowest quartile (< 5.39) were three times more likely to require PPV compared to those in the highest quartile (> 8.21).

Deep sedation for transvenous lead extraction: a large single-centre experience

Aims

Transvenous lead extraction for cardiac implantable electronic devices (CIED) is of growing importance. Nevertheless, the optimal anaesthetic approach, general anaesthesia vs. deep sedation (DS), remains unresolved. We describe our tertiary centre experience of the feasibility and safety of DS.

Methods and results

Extraction procedures were performed in the electrophysiology (EP) laboratory by two experienced electrophysiologists. We used intravenous Fentanyl, Midazolam, and Propofol for DS. A stepwise approach with locking stylets, dilator sheaths, and mechanical sheaths via subclavian, femoral, or internal jugular venous access was utilized. Patient characteristics and procedural data were collected. Logistic regression models were used to identify parameters associated with sedation-related complications. Extraction of 476 leads (dwelling time/patient 88 ± 49 months, 30% ICD leads) was performed in 220 patients (64 ± 17 years, 80% male). Deep sedation was initiated with bolus administration of Fentanyl, Midazolam, and Propofol; mean doses 0.34 ± 0.12 μg/kg, 24.3 ± 6.8 μg/kg, and 0.26 ± 0.13 mg/kg, respectively. Deep sedation was maintained with continuous Propofol infusion (initial dose 3.7 ± 1.1 mg/kg/h; subsequently increased to 4.7 ± 1.2 mg/kg/h with 3.9 ± 2.6 adjustments) and boluses of Midazolam and Fentanyl as indicated. Sedation-related episodes of hypotension, requiring vasopressors, and hypoxia, requiring additional airway management, occurred in 25 (11.4%) and 5 (2.3%) patients, respectively. These were managed without adverse consequences. Five patients (2.3%) experienced major intraprocedural complications; there were no procedure-related deaths. All of our logistic regression models indicated intraprocedural support was associated with administration higher Fentanyl doses.

Conclusion

Transvenous lead extraction under DS in the EP laboratory is a safe procedure with high success rates when performed by experienced staff.

Sodium Nitrite-Mediated Cardioprotection in Primary Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction: A Cost-Effectiveness Analysis

OBJECTIVES

In the follow-up of patients in a trial of intracoronary sodium nitrite given during primary percutaneous coronary intervention (PCI) after acute myocardial infarction (AMI), we found a reduction in the incidence of major adverse cardiac events (MACEs). Specifically, MACE rates were 5.2% versus 25.0% with placebo at 3 years ( P = .013). Such MACE reductions should also be associated with economic benefit. Thus, we assessed the cost utility of sodium nitrite therapy versus standard primary PCI only.

METHODS AND RESULTS

We developed a model to simulate costs and quality-adjusted life years (QALYs) over the first 36 months after ST-Segment Elevation Myocardial Infarction (STEMI). Decision tree analysis was used to assess different potential cardiovascular outcomes after STEMI for patients in both treatment groups. Model inputs were derived from the NITRITE-AMI study. Cost of comparative treatments and follow-up in relation to cardiovascular events was calculated from the United Kingdom National Health Service perspective. Higher procedural costs for nitrite treatment were offset by lower costs for repeat revascularization, myocardial infarction, and hospitalization for heart failure compared to primary PCI plus placebo. Nitrite treatment was associated with higher utility values (0.91 ± 0.19 vs 0.82 ± 0.30, P = .041). The calculated incremental cost-effectiveness ratio of £2177 per QALY indicates a cost-effective strategy. Furthermore, positive results were maintained when input parameters varied, indicating the robustness of our model. In fact, based on the difference in utility values, the cost of nitrite could increase by 4-fold (£2006 per vial) and remain cost-effective.

CONCLUSION

This first analysis of sodium nitrite as a cardioprotective treatment demonstrates cost-effectiveness. Although more comparative analysis and assessment of longer follow-up times are required, our data indicate the considerable potential of nitrite-mediated cardioprotection.

Remote ischemic preconditioning fails to reduce infarct size in the Zucker fatty rat model of type-2 diabetes: role of defective humoral communication

Remote ischemic preconditioning (RIPC), the phenomenon whereby brief ischemic episodes in distant tissues or organs render the heart resistant to infarction, has been exhaustively demonstrated in preclinical models. Moreover, emerging evidence suggests that exosomes play a requisite role in conveying the cardioprotective signal from remote tissue to the myocardium. However, in cohorts displaying clinically common comorbidities-in particular, type-2 diabetes-the infarct-sparing effect of RIPC may be confounded for as-yet unknown reasons. To investigate this issue, we used an integrated in vivo and in vitro approach to establish whether: (1) the efficacy of RIPC is maintained in the Zucker fatty rat model of type-2 diabetes, (2) the humoral transfer of cardioprotective triggers initiated by RIPC are transported via exosomes, and (3) diabetes is associated with alterations in exosome-mediated communication. We report that a standard RIPC stimulus (four 5-min episodes of hindlimb ischemia) reduced infarct size in normoglycemic Zucker lean rats, but failed to confer protection in diabetic Zucker fatty animals. Moreover, we provide novel evidence, via transfer of serum and serum fractions obtained following RIPC and applied to HL-1 cardiomyocytes subjected to hypoxia-reoxygenation, that diabetes was accompanied by impaired humoral communication of cardioprotective signals. Specifically, our data revealed that serum and exosome-rich serum fractions collected from normoglycemic rats attenuated hypoxia-reoxygenation-induced HL-1 cell death, while, in contrast, exosome-rich samples from Zucker fatty rats did not evoke protection in the HL-1 cell model. Finally, and unexpectedly, we found that exosome-depleted serum from Zucker fatty rats was cytotoxic and exacerbated hypoxia-reoxygenation-induced cardiomyocyte death.

Effect of initial GnRH and time of insemination on reproductive performance in cyclic and acyclic beef heifers subjected to a 5-d Co-synch plus progesterone protocol

This study evaluated the effect of initial GnRH and timing of AI in a 5-d Co-synch plus CIDR (device containing 1.38 g of progesterone) protocol on pregnancy per AI (P/AI) and pregnancy loss in beef heifers. A secondary objective was to determine if the effect of initial GnRH on reproductive performance was influenced by cyclicity. Crossbred beef heifers (n = 1068; 301-514 kg of body weight, and 13-15 mo of age) at three locations were assigned to either a 5-d Co-synch plus CIDR protocol with (CIDR5G) or without (CIDR5NG) an initial injection of 100 μg of GnRH at CIDR insertion (Day 0). All heifers received a single dose of 500 μg of cloprostenol at CIDR removal (Day 5) and were divided into two groups to receive GnRH and TAI at either 66 or 72 h (Day 8) after CIDR removal. All heifers were inseminated by one technician with frozen-thawed semen from 1 of 4 sires available commercially. Transrectal ultrasonography was performed on Day 0 to determine cyclicity (presence of CL) and normalcy of the reproductive track, and 27 d after TAI to determine pregnancy status. Non-pregnant heifers (n = 470) were assigned to either a CIDR5G or a CIDR5NG protocol with TAI at 72 h after CIDR removal. Twelve days after second AI, heifers were exposure to bulls for 20 d and pregnancy diagnoses were performed approximately 30 d after second TAI and 60 d after bulls were removed to diagnose bull pregnancies and determine pregnancy loss rate. The percentage of acyclic heifers was 20.3%. Overall P/AI after first TAI was 55.6% (594/1068) and did not differ between CIDR5G and CIDR5NG (56.1 vs. 55.1%), or between TAI66 and TAI72 (55.8 vs. 55.4%). However, cyclic heifers were more likely to become pregnant than acyclic ones (59.3 vs. 41.2%; P < 0.01). Moreover, acyclic heifers subjected to the CIDR5NG had fewer P/AI than those subjected to CIDR5G (P < 0.01). Overall P/AI after resynchronization was 55.1% and did not differ between CIDR5G and CIDR5NG (51.3 vs. 59.0%). Overall pregnancy loss after first and second TAI were 3.0% (18/594) and 3.9% (8/205), respectively. When pregnancy loss data were combined, synchronization protocol (4.1 vs. 2.3% for CIDR5NG and CIDR5G; P = 0.01), cyclicity (5.8 vs. 2.9% for acyclic and cyclic; P = 0.03) and the interaction between synchronization protocol and cyclicity (P = 0.04) were significant. The overall cumulative pregnancy at the end of the breeding season was 94.2% (1006/1068); acyclic heifers were less likely to be pregnant at the end of the breeding season (88.4 vs. 95.8%; P < 0.01). In summary, the initial GnRH administration in a 5-d Co-synch plus CIDR protocol that includes a single PGF treatment is necessary in acyclic beef heifers to optimize P/AI, but not in cyclic heifers. Moreover, omission of initial GnRH was associated to greater pregnancy losses, particularly in acyclic heifers. Timing of AI did not affect P/AI.

Ischemic Conditioning Attenuates Platelet-Mediated Thrombosis

Data obtained in both preclinical models and humans have revealed that the favorable cardiac consequences of ischemic conditioning extend beyond a direct effect on the cardiomyocyte. In the current review, we summarize our as-yet limited understanding of the complex relationships between ischemic conditioning, platelet activation–aggregation, and cardioprotection.

Remote Ischemic Preconditioning: Current Knowledge, Unresolved Questions, and Future Priorities

Remote ischemic preconditioning (RIPC) is the phenomenon whereby brief episodes of ischemia–reperfusion applied in distant tissues or organs render the myocardium resistant to a subsequent sustained episode of ischemia. Reduction of infarct size with RIPC has been documented in response to (i) brief antecedent ischemia in a remote coronary vascular bed (intra-cardiac protection); (ii) collection and transfer of coronary effluent from perconditioning “donor” hearts to naive “receptor” hearts (inter-cardiac protection); (iii) brief ischemia applied in skeletal muscle, mesentery, and other organs (interorgan protection); and (iv) remote nociception (“remote PC of trauma”). Moreover, the paradigm has expanded to encompass temporal modifications in the application of the remote stimulus (remote perconditioning and remote postconditioning). Progress has also been made in translating the concept of RIPC to patients undergoing planned ischemic events: evidence for attenuation of cardiac enzyme release with RIPC has been reported after elective abdominal aortic aneurysm repair, angioplasty, and coronary artery bypass graft surgery. However, despite these advances in characterization and clinical application, the mechanisms of RIPC—most notably, the means by which the protective stimulus is communicated to the heart—remain poorly defined and, in all likelihood, are model dependent.

Calcium Administration Is Associated with Adverse Outcomes in Critically Ill Patients Receiving Parenteral Nutrition: Results from a Natural Experiment Created by a Calcium Gluconate Shortage

STUDY OBJECTIVE

Parenteral calcium is frequently administered to critically ill patients. However, animal studies demonstrate that calcium administration during critical illness heightens inflammation and leads to shock, organ dysfunction, and mortality. We sought to evaluate the association between calcium administration and adverse outcomes in critically ill patients receiving parenteral nutrition (PN).

DESIGN

Retrospective cohort examined before and during a calcium gluconate shortage. During the shortage, calcium was absent from PN, but calcium supplementation outside of PN was allowed. The shortage resulted in a natural experiment that included a group of patients who did not receive calcium.

SETTING

Intensive care units (ICUs) in three teaching hospitals.

PATIENTS

A total of 259 adults who received PN in the ICU for 48 hours or longer.

MEASUREMENTS AND MAIN RESULTS

Patients were divided into quartiles based on amount of parenteral calcium received; the lowest quartile received no calcium. End points were in-hospital mortality, acute respiratory failure, new-onset shock, and a composite of any one of these end points. For patients not on mechanical ventilation or vasoactive support when PN started, logistic regression revealed that calcium administration was associated with mortality (odds ratio [OR] 2.48, 95% confidence interval [CI] 1.08-5.69), acute respiratory failure (OR 2.43, 95% CI 1.28-4.60), new-onset shock (OR 2.81, 95% CI 1.22-6.44), and the combined end point (OR 2.33, 95% CI 1.31-4.16). The odds of adverse outcomes increased as the calcium dose increased.

CONCLUSION

Calcium administration correlated with adverse outcomes in critically ill patients receiving PN. The data suggest that administration of parenteral calcium to critically ill patients may be harmful.

12 INITIAL GONADOTROPIN-RELEASING HORMONE TREATMENT INCREASED PREGNANCY PER TIMED INSEMINATION ONLY IN ACYCLIC BEEF HEIFERS SUBJECTED TO A 5-DAY CO-SYNCH PROTOCOL

We have shown that inclusion of initial gonadotropin-releasing hormone (GnRH) in a 5-day Co-synch protocol is unnecessary to achieve acceptable pregnancy rates in dairy heifers (2011 Theriogenology 76, 578). This study determined the efficacy of a modified (without initial GnRH) 5-day Co-synch protocol for timed AI (TAI) and the effect of interval from progesterone device removal to TAI on pregnancy per TAI (P/TAI) in acyclic and cyclic beef heifers. Heifers (n = 1062; 302 to 515 kg of body weight, and 13 to 15 months of age) at 2 locations were assigned to either a 5-day Co-synch protocol with (control) or without (modified) an initial injection of 100 μg of GnRH (Fertagyl; Merck Animal Health, Kenilworth, NJ, USA) at progesterone device (CIDR; Zoetis Animal Health, Florham Park, NJ) insertion (Day 0). All heifers received a single dose of 500 μg of cloprostenol (Estrumate; Merck Animal Health) at CIDR removal (Day 5) and were divided into 2 groups to receive GnRH and simultaneously TAI at either 66 or 72 h (Day 8) after CIDR removal. All heifers were inseminated by one technician with frozen-thawed semen from 1 of 4 commercially available sires. Ovarian ultrasonography was performed on Day 0 to determine cyclicity (presence of corpus luteum) and normalcy of the reproductive track, and on Day 35 (27 days after TAI) to determine pregnancy status. Data were analysed using the PROC GLIMMIX in SAS (SAS Institute Inc., Cary, NC, USA). The CIDR retention rate was 98%; P/TAI in heifers that lost the CIDR was 39%. Pregnancy per TAI [least squares means (n)] did not differ (P > 0.05) among sires [48 (235), 51 (318), 52 (274), and 53% (235)], location [57 (330) v. 53% (732)], timing of TAI [52 (533) v. 50% (529) for 66 and 72 h], or treatment groups [48 (525) v. 53% (537) for control and modified groups]. A total of 226 (21%) heifers were acyclic; P/TAI was lower in acyclic heifers compared with that in those cyclic (P < 0.01; 43 v. 59%). Administration of GnRH at CIDR insertion increased P/TAI in acyclic heifers (P < 0.01; 50 v. 35% for control and modified groups) but did not affect P/TAI in those that were cyclic at initiation of protocol (P > 0.05; 57 v. 62% for control and modified groups). In conclusion, timing of TAI did not affect fertility. However, administration of initial GnRH increased P/TAI by 15 percentiles in acyclic females, but as previously shown in Holstein heifers, initial GnRH was unnecessary to achieve acceptable P/TAI in cyclic beef heifers subjected to a 5-days Co-synch protocol. This study was supported by Alberta Agriculture and Forestry, Intervet Canada Corp., and collaborative beef producers.

Remote ischemic conditioning and renal function after contrast-enhanced CT scan: A randomized trial

PURPOSE

Remote ischemic conditioning has been shown to protect against kidney injury in animal and human studies of ischemia-reperfusion. Recent evidence suggests that conditioning may also provide protection against kidney injury caused by contrast medium. The purpose of this study was to determine if conditioning protected against increases in serum creatinine (SCr) after contrast-enhanced computed tomography (CECT).

METHODS

A randomised controlled trial (NCT 01741896) was performed with institutional review board approval and informed patient consent. Adult in-patients undergoing abdomino-pelvic CECT were allocated to conditioned or control groups. Conditioning consisted of four cycles of five minutes of cuff-induced arm ischemia with three minutes of reperfusion applied ~40 minutes before CECT. The primary outcome was SCr change after CECT.

RESULTS

Baseline characteristics were similar in both groups. For all patients, conditioning reduced the risk ratio (RR) of increased SCr; RR 0.65 (95% confidence intervals 0.41 to 1.04). The protective effect was greater and the evidence for protection stronger when analysis was restricted to patients with pre-scan reduced renal function (eGFR.

From ischemic conditioning to 'hyperconditioning': clinical phenomenon and basic science opportunity

Thousands of articles have been published on the topic of ischemic conditioning. Nevertheless, relatively little attention has been given to assessment of conditioning's dose-response characteristics. Specifically, the consequences of multiple conditioning episodes, what we will term "hyperconditioning", have seldom been examined. We propose that hyperconditioning warrants investigation because it; (1) may be of clinical importance, (2) could provide insight into conditioning mechanisms, and (3) might result in development of novel models of human disease. The prevalence of angina pectoris and intermittent claudication is sufficiently high and the potential for daily ischemia-reperfusion episodes sufficiently large that hyperconditioning is a clinically relevant phenomenon. In basic science, attenuation of conditioning-mediated infarct size reduction found in some studies after hyperconditioning offers a possible means to facilitate further discernment of cardioprotective signaling pathways. Moreover, hyperconditioning's impact extends beyond cytoprotection to tissue structural elements. Several studies demonstrate that hyperconditioning produces collagen injury (primarily fiber breakage). Such structural impairment could have adverse clinical consequences; however, in laboratory studies, selective collagen damage could provide the basis for models of cardiac rupture and dilated cardiomyopathy. Accordingly, we propose that hyperconditioning represents the dark, but potentially illuminating, side of ischemic conditioning - a paradigm that merits attention and prospective evaluation.

Point-of-care assessment of platelet reactivity in the emergency department may facilitate rapid rule-out of acute coronary syndromes: a prospective cohort pilot feasibility study

OBJECTIVE

Accurate, efficient and cost-effective disposition of patients presenting to emergency departments (EDs) with symptoms suggestive of acute coronary syndromes (ACS) is a growing priority. Platelet activation is an early feature in the pathogenesis of ACS; thus, we sought to obtain an insight into whether point-of-care testing of platelet function: (1) may assist in the rule-out of ACS; (2) may provide additional predictive value in identifying patients with non-cardiac symptoms versus ACS-positive patients and (3) is logistically feasible in the ED.

DESIGN

Prospective cohort feasibility study.

SETTING

Two urban tertiary care sites, one located in the USA and the second in Argentina.

PARTICIPANTS

509 adult patients presenting with symptoms of ACS.

MAIN OUTCOME MEASURES

Platelet reactivity was quantified using the Platelet Function Analyzer-100, with closure time (seconds required for blood, aspirated under high shear, to occlude a 150 µm aperture) serving as the primary endpoint. Closure times were categorised as 'normal' or 'prolonged', defined objectively as the 90th centile of the distribution for all participants enrolled in the study. Diagnosis of ACS was made using the standard criteria. The use of antiplatelet agents was not an exclusion criterion.

RESULTS

Closure times for the study population ranged from 47 to 300 s, with a 90th centile value of 138 s. The proportion of patients with closure times ≥138 s was significantly higher in patients with non-cardiac symptoms (41/330; 12.4%) versus the ACS-positive cohort (2/105 (1.9%); p=0.0006). The specificity of 'prolonged' closure times (≥138 s) for a diagnosis of non-cardiac symptoms was 98.1%, with a positive predictive value of 95.4%. Multivariate analysis revealed that the closure time provided incremental, independent predictive value in the rule-out of ACS.

CONCLUSIONS

Point-of-care assessment of platelet reactivity is feasible in the ED and may facilitate the rapid rule-out of ACS in patients with prolonged closure times.

Genesis of remote conditioning: action at a distance--'hypotheses non fingo'?

Remote ischemic preconditioning is the phenomenon whereby brief episodes of ischemia-reperfusion applied in a distant organ or tissue render the myocardium resistant to infarction. The discovery of remote conditioning was not a serendipitous finding, but, rather, was predicted by mathematical modeling. In the current review, we describe how the hypothesis for remote conditioning was formulated and tested, how the paradigm has expanded to encompass a spectrum of remote triggers, and summarize the progress that has been made in elucidating the mechanisms responsible for this intriguing form of cardioprotection.

Venous thromboembolism in an industrial north american city: temporal distribution and association with particulate matter air pollution

BACKGROUND

Emerging evidence, mainly from Europe and Asia, indicates that venous thromboembolism (VTE) occurs most often in winter. Factors implicated in such seasonality are low temperature-mediated exacerbation of coagulation and high levels of particulate matter (PM) air pollution. However, in contrast to most European and Asian cities, particulate matter pollution peaks in the summer in many North American cities.

OBJECTIVES

We aimed to exploit this geographical difference and examine the temporal distribution of VTE in a cold-weather, North American city, Detroit, with a summer PM peak. Our goal was thereby to resolve the influence of temperature and PM levels on VTE.

METHODS

Our retrospective, analytical semi-ecological study used chart review to confirm 1,907 acute, ambulatory VTE cases, divided them by location (Detroit versus suburban), and plotted monthly VTE frequency distributions. We used Environmental Protection Agency data to determine the temporal distribution of PM pollution components in Detroit. Suburban PM air pollution is presumed negligible and therefore not monitored.

RESULTS

Acute VTE cases in Detroit (1,490) exhibited a summer peak (June 24(th)) and differed from both a uniform distribution (P<0.01) and also that of 1,123 no-VTE cases (P<0.02). Levels of 10 µm diameter PM and coarse particle (2.5 to 10 µm) PM also exhibited summer peaks versus a winter peak for 2.5 µm diameter PM. Contrary to their urban counterparts, suburban cases of acute VTE (417) showed no monthly variation.

CONCLUSIONS

The summer peak of acute VTE in Detroit indicates that low temperature is not a major factor in VTE pathogenesis. In contrast, concordance of the 10 µm diameter PM, coarse particle, and the Detroit VTE monthly distributions, combined with no monthly suburban VTE variation, is consistent with a role for PM pollution. Furthermore, divergence of the VTE and 2.5 µm PM distributions suggests that particle size may play a role.

Kidney dysfunction at the time of intracerebral hemorrhage is associated with increased in-hospital mortality: a retrospective observational cohort study

OBJECTIVE

Renal dysfunction has been implicated as a risk factor for adverse outcomes after numerous cardiovascular events including stroke. However, most of the stroke studies have focused on long-term results and have primarily examined ischemic stroke. Therefore, we aimed to determine if renal dysfunction was associated with increased initial in-hospital mortality after intracerbral hemorrhage (ICH).

METHODS

Our retrospective, observational, cohort chart review evaluated the relationship between in-hospital mortality after ICH and renal function, assessed from admission estimated glomerular filtration rate (eGFR), calculated using the abbreviated modification of diet in renal disease equation, in 101 consecutive cases.

RESULTS

Survivors had higher admission eGFRs than those who died (88 ± 37 versus 59 ± 33 ml/minute/1.73 m(2); P<0.001). Similarly, mortality was higher in patients with eGFR <90 versus those >90 ml/minute/1.73 m(2) (40% versus 15%; P = 0.009). Univariate analysis indicated that in-hospital death was associated with intraventricular hemorrhage, ICH volume, age, eGFR <90 ml/minute/1.73 m(2), and admission values of serum creatinine, and blood urea nitrogen (P<0·05). Multivariable logistic regression (controlled for confounding variables) revealed that admission eGFR was an independent predictor of death; odds ratio 0.96; 95% confidence interval 0.92-0.99. We also found a negative correlation between eGFR and lesion size (P = 0.041); the lower the eGFR, the larger the lesion.

CONCLUSION

Renal dysfunction was an independent predictor of initial in-hospital mortality after stroke and hence may stratify risk in ICH patients.

Autophagy as a therapeutic target for ischaemia /reperfusion injury? Concepts, controversies, and challenges

Autophagy is the tightly orchestrated cellular 'housekeeping' process responsible for the degradation and disposal of damaged and dysfunctional organelles and protein aggregates. In addition to its established basal role in the maintenance of normal cellular phenotype and function, there is growing interest in the concept that targeted modulation of autophagy under conditions of stress (most notably, ischaemia/reperfusion) may represent an adaptive mechanism and render the myocardium resistant to ischaemia/reperfusion injury. Our aims in this review are to: (i) provide a balanced overview of the emerging hypothesis that perturbation of autophagy may serve as a novel, intriguing, and powerful cardioprotective treatment strategy and (ii) summarize the controversies and challenges in exploiting autophagy as a therapeutic target for ischaemia/reperfusion injury.

Remote-conditioning ischemia provides a potential approach to mitigate contrast medium-induced reduction in kidney function: a retrospective observational cohort study

Contrast medium administration during imaging and therapeutic procedures can cause renal injury, partly due to ischemia. Therefore, we hypothesized that brief ischemia and reperfusion episodes applied at a distant site - multiple balloon inflations and deflations during angioplasty - may serve as a remote-conditioning (RC) stimulus and thereby protect against contrast-induced kidney injury. To test this hypothesis, we (1) utilized cases from a prior study in which patients undergoing emergent angioplasty for ST segment elevation myocardial infarction received either 1-3 balloon inflations (controls) or were 'conditioned' with multiple (≥4) inflations, and (2) assessed renal function for 3 days in patients with an estimated glomerular filtration rate (eGFR) of <90 ml/min/1.73 m(2) prior to revascularization (mild kidney disease). Both groups displayed increased eGFR at day 1 after angioplasty versus baseline; attributed to in-hospital hydration (control: 77 ± 14 vs. 68 ± 12 ml/min/1.73 m(2); p < 0.01; RC: 81 ± 21 vs. 69 ± 12 ml/min/1.73 m(2); p < 0.01). In controls, this improvement was transient: eGFR subsequently decreased to 70 ± 14 ml/min/1.73 m(2) at day 3 (p < 0.05). In contrast, the RC group (despite receiving 25% more contrast volume) showed no functional decline at day 3 (80 ± 14 ml/min/1.73 m(2)). These results are consistent with remote ischemic conditioning providing a novel potential approach to attenuate contrast-associated renal injury.

Effect of chronic kidney disease on warfarin management in a pharmacist-managed anticoagulation clinic

BACKGROUND

There is growing evidence that kidney disease affects hepatically cleared drugs. Accordingly, we hypothesized that chronic kidney disease (CKD) would disrupt anticoagulation of warfarin-treated patients and thereby increase the amount of management required to maintain appropriate anticoagulation. Specifically, we anticipated that more dose manipulations (both dose changes and transient dose adjustments) and shorter times between scheduled clinic visits would be required for anticoagulation patients with CKD.

OBJECTIVES

To determine how CKD affected warfarin maintenance dose, anticoagulation stability, the proportion of clinic visits that necessitated a dose manipulation (either a change in the prescribed weekly dose or a transient dose adjustment), and the length of time between scheduled visits in 2 pharmacist-managed anticoagulation clinics.

METHODS

Our retrospective, cohort chart review investigated warfarin response in anticoagulation clinic patients. From the clinic database of patients with an international normalized ratio (INR) target range of 2.0-3.0, we matched 20 of 24 patients with CKD (estimated creatinine clearance less than 60 mL per minute) to 20 comparison group patients (estimated creatinine clearance greater than 60 mL per minute) based on parameters demonstrated to affect warfarin dose: ethnicity, gender, age, body surface area, and simvastatin use. We calculated the average weekly dose used to maintain target INR (assessment period range=116-1,408 days). To evaluate anticoagulation stability and patient management, we quantified several parameters, including the percentage of total time in therapeutic range, the proportion of clinic visits that required a dose change, and the time between scheduled visits. We compared group means using t-tests, and categorical data were compared using Fisher's exact test.

RESULTS

Our population was predominantly female (75%) and of African ancestry (95%); average age 60 years. Patients with CKD required a 24% lower dose than the comparison group (mean [SD]=35.9 [10.7] vs. 47.0 [11.2] mg per week, P=0.003) and spent less time in therapeutic range required increased clinic management versus the comparison group, as indicated by a significantly higher proportion of clinic visits at which dose changes occurred (22% vs. 12%, P<0.001) and a decreased time between scheduled visits (mean [SD] of 16.0 [3.2] days vs. 19.7 [3.4] days, respectively, P=0.001).

CONCLUSIONS

CKD was associated with both decreased warfarin maintenance dose and decreased anticoagulation stability which, in turn, required more frequent and intensive anticoagulation clinic management.

Cardioprotection with postconditioning: loss of efficacy in murine models of type-2 and type-1 diabetes

Postconditioning (PostC), or relief of myocardial ischemia in a stuttered manner, has been shown to reduce infarct size, due in part to upregulation of survival kinase signaling. Virtually all of these data have, however, been obtained in healthy adult cohorts; the question of whether PostC-induced cardioprotection is maintained in the setting of clinically relevant comorbidities has remained largely unexplored. Accordingly, our aim was to assess the consequences of a major risk factor-diabetes-on the infarct-sparing effect of stuttered reflow. Isolated buffer-perfused hearts were obtained from normoglycemic C57BL/6J mice, BKS.Cg-m+/+Lepr(db)/J (db/db) mice (model of type-2 diabetes), C57BL/6J mice injected with streptozotocin (model of type-1 diabetes), and streptozotocin-injected mice in which normoglycemia was re-established by islet cell transplantation. All hearts underwent 30  min of ischemia and, within each cohort, hearts received either standard (control) reperfusion or three to six 10-s cycles of stuttered reflow. PostC reduced infarct size via upregulation of extracellular signal-regulated kinase 1/2 in normoglycemic mice. In contrast, diabetic hearts were refractory to PostC-induced cardioprotection-an effect that, in the type-1 model, was reversed by restoration of normoglycemia. We provide novel evidence for a profound-but potentially reversible-diabetes-induced defect in the cardioprotective efficacy of PostC.

Authorship and Characteristics of Articles in Pharmacy Journals: Changes Over a 20-Year Interval

Background:

To our knowledge, no studies have evaluated authorship patterns and characteristics of articles in pharmacy journals,

Objective:

To investigate changes over a 20-year period in authorship and characteristics of articles in pharmacy journals.

Methods:

All articles published in the American Journal of Health-System Pharmacy, The Annals of Pharmacotherapy, and Pharmacotherapy in 1989, 1999, and 2009 were reviewed. Data collected for each article included article type, number of authors, number of physician authors, whether any author was affiliated with a pharmaceutical company, and source of funding.

Results:

The number of articles included was 574 in 1989, 659 in 1999, and 589 in 2009. The mean number of authors per article increased from 2.5 in 1989 to 2.8 in 1999 and 3.6 in 2009 (p< 0.001). Conversely, the proportion of articles with a single author decreased from 35% in 1989 to 23% in 1999 and 11 % in 2009 (p < 0.001), while the proportion of multi-authored articles (>6 authors) increased from 2% in 1989 to 3% in 1999 and 9% in 2009 (p < 0.001). A physician author was listed on 25% of papers in 1989, which increased to 38% in 1999 and 41% in 2009 (p < 0.001). Among research articles with declared funding from industry, there was an increase over time in reported author affiliation with an industry sponsor (10% of articles in 1989, 17% in 1999, and 66% in 2009; p < 0.001).

Conclusions:

Significant changes in authorship patterns and characteristics of articles were observed from 1989 to 2009. We found an increase in the number of authors per article over time, with fewer single-author papers now published. The explanations for the changes are likely multifactorial, including increased pressure to publish, increased research complexity, and inappropriate authorship. To prevent inappropriate author-number inflation and to preserve authorship's meaning and value, authors should adhere to the criteria for authorship from the International Committee of Medical Journal Editors.

Targeted inhibition of the serotonin 5HT2A receptor improves coronary patency in an in vivo model of recurrent thrombosis

BACKGROUND

Release of serotonin and activation of serotonin 5HT2A receptors on platelet surfaces is a potent augmentative stimulus for platelet aggregation. However, earlier-generation serotonin receptor antagonists were not successfully exploited as antiplatelet agents, possibly owing to their lack of specificity for the 5HT2A receptor subtype.

OBJECTIVE

To assess whether targeted inhibition of the serotonin 5HT2A receptor attenuates recurrent thrombosis and improves coronary patency in an in vivo canine model mimicking unstable angina.

METHODS

In protocol 1, anesthetized dogs were pretreated with a novel, selective inverse agonist of the 5HT2A receptor (APD791) or saline. Recurrent coronary thrombosis was then initiated by coronary artery injury+stenosis, and coronary patency was monitored for 3 h. Protocol 2 was similar, except that: (i) treatment with APD791 or saline was begun 1 h after the onset of recurrent thrombosis; (ii) template bleeding time was measured; and (iii) blood samples were obtained for in vitro flow cytometric assessment of platelet responsiveness to serotonin.

RESULTS

APD791 attenuated recurrent thrombosis, irrespective of the time of treatment: in both protocols, flow-time area (index of coronary patency; normalized to baseline coronary flow) averaged 58-59% (P<0.01) following administration of APD791 vs. 21-28% in saline controls. Moreover, the in vivo antithrombotic effect of APD791 was not accompanied by increased bleeding, but was associated with significant and selective inhibition of serotonin-mediated platelet activation.

CONCLUSION

5HT2A receptor inhibition with APD791, even when initiated after the onset of recurrent thrombosis, improves coronary patency in the in vivo canine model.

Lamina propria cellularity and collagen composition: an integrated assessment of structure in humans

OBJECTIVES

In this study, we quantitatively examined cell density, collagen types I and III, and regional variations in collagen fiber thickness and orientation in the human midmembranous vocal fold lamina propria (LP).

METHODS

Lamina propria samples were solubilized with proteinase K or with cyanogen bromide. Cell density was assessed in proteinase K digests by measuring DNA and normalizing it to tissue total protein. Collagen types I and III were quantified by enzyme-linked immunosorbent assay-based detection of collagen type-specific peptides generated by cyanogen bromide digestion. In addition, LP total collagen was determined by measuring sample hydroxyproline levels. Variations in collagen fiber thickness and orientation with LP region were evaluated by examining picrosirius red-stained LP sections with circularly polarized light.

RESULTS

The mean (+/-SEM) cell density in the LP and associated epithelium was approximately 0.57 +/- 0.09 million cells per milligram of tissue total protein. Collagen type III composed an average of 34% to 40% of LP total collagen. Quantitative histology indicated that the superficial LP contained an average of 70% thin, 26% intermediate, and 4% thick collagen fibers. This is in contrast to the intermediate and deep LPs, each of which contained less than 25% thin and more than 50% thick collagen fibers. The angular deviations in collagen fiber orientation were relatively large and were similar in magnitude across all LP layers.

CONCLUSIONS

The total cell density of the LP and associated epithelium was intermediate between that of hyaline cartilage and dermis. The ratio of collagen type III to total collagen in the LP was similar to that of highly elastic lung parenchyma and roughly twice that of the comparatively less-elastic dermis. The average thickness of collagen fibers increased markedly with increasing LP depth, and the relatively large angular deviations in fiber orientation appeared to correspond in part to the crimped nature of LP collagen fibers.

Genetically engineered resistance for MMP collagenases promotes abdominal aortic aneurysm formation in mice infused with angiotensin II

Clinical evidence links increased aortic collagen content and stiffness to abdominal aortic aneurysm (AAA) formation. However, the possibility that excess collagen contributes to AAA formation remains untested. We investigated the hypothesis that augmented collagen promotes AAA formation, and employed apoE-null mice expressing collagenase-resistant mutant collagen (Col(R/R)/apoE(-/-)), heterozygote (Col(R/+)/apoE(-/-)), or wild-type collagen (Col(+/+)/apoE(-/-)) infused with angiotensin II to induce AAA. As expected, the aortas of Col(R/R)/apoE(-/-) mice contained more interstitial collagen than those from the other groups. Angiotensin II treatment elicited more AAA formation in Col(R/R)/apoE(-/-) mice than Col(R/+)/apoE(-/-) or Col(+/+)/apoE(-/-) mice. Aortic circumferences correlated positively with collagen content, determined by picrosirius red and Masson trichrome staining. Mechanical testing of aortas of Col(R/R)/apoE(-/-) mice showed increased stiffness and susceptibility to mechanical failure compared to those of Col(+/+)/apoE(-/-) mice. Optical analysis further indicated altered collagen fiber orientation in the adventitia of Col(R/R)/apoE(-/-) mice. These results demonstrate that collagen content regulates aortic biomechanical properties and influences AAA formation.

Haplotype-based search for SNPs associated with differential type 1 diabetes risk among chromosomes carrying a specific HLA DRB1-DQA1-DQB1 haplotype

AIM

The aim of this study was to test chromosomes carrying the same DRB1-DQA1-DQB1 haplotype for single nucleotide polymorphisms (SNPs) in the major histocompatibility complex (MHC) that might mark subgroups of the haplotype with different risks for type 1 diabetes (T1D).

METHODS

Chromosomes from T1D children, their parents and non-diabetic siblings in families of the Type 1 Diabetes Genetics Consortium (T1DGC) were analysed by two haplotype-based methods: (i) logistic regression analysis restricted to phased chromosomes carrying the same DRB1-DQA1-DQB1 haplotype but differentiated by the two alleles at MHC SNPs, which were individually tested for association with T1D and (ii) homozygous parent transmission disequilibrium test (TDT) for biased transmission of a SNP allele to diabetic children from parents who are heterozygous at the SNP but homozygous for the specific DRB1-DQA1-DQB1 haplotype being evaluated.

RESULTS

A number of SNPs gave nominally significant (p < 0.05) evidence of marking two subsets of the 301-501-201 haplotype that might differ with respect to their diabetogenic potency. However, none of the SNPs achieved experiment-wide significance and hence may be false-positive associations.

CONCLUSIONS

We discuss limitations and possible deficiencies of our study suggesting further work that might yield more robust SNP associations marking two subgroups of a DRB1-DQA1-DQB1 haplotype with different T1D risks.

Fibrin architecture in clots: a quantitative polarized light microscopy analysis

Fibrin plays a vital structural role in thrombus integrity. Thus, the ability to assess fibrin architecture has a potential to provide insight into thrombosis and thrombolysis. Fibrin has an anisotropic molecular structure, which enables it to be seen with polarized light. Therefore, we aimed to determine if automated polarized light microscopy methods of quantifying two structural parameters; fibrin fiber bundle orientation and fibrin's optical retardation (OR: a measure of molecular anisotropy) could be used to assess thrombi. To compare fibrin fiber bundle orientation we analyzed picrosirius red-stained sections obtained from clots formed: (A) in vitro, (B) in injured and stenotic coronary arteries, and (C) in surgically created aortic aneurysms (n=6 for each group). To assess potential changes in OR, we examined fibrin in picrosirius red-stained clots formed after ischemic preconditioning (10 min ischemia+10 min reflow; a circumstance shown to enhance lysability) and in control clots (n=8 each group). The degree of fibrin organization differed significantly according to the location of clot formation; fibrin was most aligned in the aneurysms and least aligned in vitro whereas fibrin in the coronary clots had an intermediate organization. The OR of fibrin in the clots formed after ischemic preconditioning was lower than that in controls (2.9+/-0.5 nm versus 5.4+/-1.0 nm, P<0.05). The automated polarized light analysis methods not only enabled fibrin architecture to be assessed, but also revealed structural differences in clots formed under different circumstances.

Genetic association analyses of non-synonymous single nucleotide polymorphisms in diabetic nephropathy

AIMS/HYPOTHESIS

Diabetic nephropathy, characterised by persistent proteinuria, hypertension and progressive kidney failure, affects a subset of susceptible individuals with diabetes. It is also a leading cause of end-stage renal disease (ESRD). Non-synonymous (ns) single nucleotide polymorphisms (SNPs) have been reported to contribute to genetic susceptibility in both monogenic disorders and common complex diseases. The objective of this study was to investigate whether nsSNPs are involved in susceptibility to diabetic nephropathy using a case-control design.

METHODS

White type 1 diabetic patients with (cases) and without (controls) nephropathy from eight centres in the UK and Ireland were genotyped for a selected subset of nsSNPs using Illumina's GoldenGate BeadArray assay. A chi (2) test for trend, stratified by centre, was used to assess differences in genotype distribution between cases and controls. Genomic control was used to adjust for possible inflation of test statistics, and the False Discovery Rate method was used to account for multiple testing.

RESULTS

We assessed 1,111 nsSNPs for association with diabetic nephropathy in 1,711 individuals with type 1 diabetes (894 cases, 817 controls). A number of SNPs demonstrated a significant difference in genotype distribution between groups before but not after correction for multiple testing. Furthermore, neither subgroup analysis (diabetic nephropathy with ESRD or diabetic nephropathy without ESRD) nor stratification by duration of diabetes revealed any significant differences between groups.

CONCLUSIONS/INTERPRETATION

The nsSNPs investigated in this study do not appear to contribute significantly to the development of diabetic nephropathy in patients with type 1 diabetes.

Bone mineral density, osteoporosis, and osteoporotic fractures: a genome-wide association study

BACKGROUND

Osteoporosis is diagnosed by the measurement of bone mineral density, which is a highly heritable and multifactorial trait. We aimed to identify genetic loci that are associated with bone mineral density.

METHODS

In this genome-wide association study, we identified the most promising of 314 075 single nucleotide polymorphisms (SNPs) in 2094 women in a UK study. We then tested these SNPs for replication in 6463 people from three other cohorts in western Europe. We also investigated allelic expression in lymphoblast cell lines. We tested the association between the replicated SNPs and osteoporotic fractures with data from two studies.

FINDINGS

We identified genome-wide evidence for an association between bone mineral density and two SNPs (p<5x10(-8)). The SNPs were rs4355801, on chromosome 8, near to the TNFRSF11B (osteoprotegerin) gene, and rs3736228, on chromosome 11 in the LRP5 (lipoprotein-receptor-related protein) gene. A non-synonymous SNP in the LRP5 gene was associated with decreased bone mineral density (rs3736228, p=6.3x10(-12) for lumbar spine and p=1.9x10(-4) for femoral neck) and an increased risk of both osteoporotic fractures (odds ratio [OR] 1.3, 95% CI 1.09-1.52, p=0.002) and osteoporosis (OR 1.3, 1.08-1.63, p=0.008). Three SNPs near the TNFRSF11B gene were associated with decreased bone mineral density (top SNP, rs4355801: p=7.6x10(-10) for lumbar spine and p=3.3x10(-8) for femoral neck) and increased risk of osteoporosis (OR 1.2, 95% CI 1.01-1.42, p=0.038). For carriers of the risk allele at rs4355801, expression of TNFRSF11B in lymphoblast cell lines was halved (p=3.0x10(-6)). 1883 (22%) of 8557 people were at least heterozygous for these risk alleles, and these alleles had a cumulative association with bone mineral density (trend p=2.3x10(-17)). The presence of both risk alleles increased the risk of osteoporotic fractures (OR 1.3, 1.08-1.63, p=0.006) and this effect was independent of bone mineral density.

INTERPRETATION

Two gene variants of key biological proteins increase the risk of osteoporosis and osteoporotic fracture. The combined effect of these risk alleles on fractures is similar to that of most well-replicated environmental risk factors, and they are present in more than one in five white people, suggesting a potential role in screening.

Human stem cells and their storage: some ethical issues

An account of the sources and properties of human stem cells is given with an indication of ethical issues associated with each. The ethical considerations of umbilical cord blood stem cell banks are considered in more detail. It is suggested that some private stem cell banks may not, at present, be providing an ethically valid service. Public stem cell banks, on the other hand, may be more likely to save lives although it will be necessary to assure their long-term financial status.